Ignition system



jme L i9@ H, P. Quimm 3,387,222

IGNXTION SYSTEM Filed March 23, 1962 ffy Tuc'l- INVENTOR M114, SEY R @www ATTORNE ya? United States Patent Otiice 3,187,222 Patented `lune 1, 1965 3,187,222 IGNITION SYSTEM Haisey P. Quinn, Morris Plains, NJ., assigner to Tung- Sol Electric Inc., a corporation of Delaware Filed Mar. 23, 1962, Ser. No. 181,992 4 Claims. (Cl. 315-209) This invention relates to an ignition system for internal combustion engines. It has special reference to the application of an ignition circuit for slow speed motors and is directed to the reduction of battery current for such installation power. The invention also relates to an ignition circuit which is compensated for the low voltage generally available during the time the starter motor is turning over the engine.

All the modern ignition circuits now used on passenger cars employ a storage battery and breaker points which, with other coupled circuits, generate a high voltage which is applied to spark plugs for igniting a mixture within a piston chamber. All of these devices are somewhat ineicient because when the breaker points are closed the battery discharges through the circuit and much of this current drain provides no usell result. The present invention restricts this current flow to a portion of the engine cycle and thereby limits the battery current to one-third or one-half of the usual current depending upon the speed of the engine. The saving is greatest while the engine is turning at slow speeds. In addition to saving primary current, the system produces a fast rise time `and an intense spark in the combustion chambers even though the spark plugs may have considerable leakage resistance.

One of vthe objects of this invention is -to provide an improved ignition system which avoids one or more of the disadvantages and limitations of prior art circuits.

Another object of the invention is to provide an electronic ignition system which is compatible with modern day automobile ignition systems.

Another object of the invention is to reduce the battery drain during the slow speed operation of the engine.

Another object of the invention is to compensate for the low battery voltage when the engine is being started by the starter motor.

Another object of the invention is to reduce the generation of heat in a transistor during slow operating speeds.

The invention comprises an ignition system for internal combustion engines having a spark plug in each combustion chamber and includes a source of direct current, a primary circuit which includes the power source, the primaries -of two control transformers and the emittercollector circuit of a transistor. The operation of this primary circuit is controlled by the opening and closing of a set of breaker contacts. The system also includes a charging circuit for charging a storage capacitor. This circuit includes the secondary of a charging transformer, the storage capacitor, a diode rectifier, and the primary of an output transformer. A discharge circuit includes the above mentioned storage capacitor and primary winding plus a gaseous discharge device which is controlled by a firing electrode coupled to a secondary winding of a tiring transformer. The output circuit includes the secondary winding of the output transformer plus a distributor and a number of spark plugs set in the ignition chambers of the engine.

For a better understanding of the present invention, together with -other and further objects thereof, reference is made to the following description taken in connection with the accompanying drawings.

FIG. 1 is a schematic diagram of connections of the system.

FIG. 2A is a graph showing the usual current present in prior art circuits.

FG. 2B is a graph showing the currents and voltages in the present invention.

FIG. 3 is a diagrammatic representation of a. transformer which can be used with this system.

FIG. 4 is similar to FIG. 3 but showing an alternative transformer design.

FIG. 5 shows an alternative coupling between the charging transformer and the ring electrode of the discharge device.

Referring now to FIG. 1, the circuit includes a battery 10, a pair of breaker points 11 operated by a cam 12 which is turned by a shaft 13 coupled to the distributor and to the pistons (not shown) -in the engine. The battery 10 and the contact points 11 are connected in series with a limiting resistor 14 and the primary Winding 15 of a control transformer 16. The usual ignition switch 17 is connected in series with this circuit and must be closed when the circuit is in operation.

Control transformer 16 has a secondary winding 1S Which is connected to the base and emitter electrodes of a transistor 20, the collector of this transistor being connected to ground and to the negative terminal of battery 10. One end of secondary winding 18 is connected in series with a primary winding 21 of a tiring transformer 22 and the primary Winding 23 of a charging transformer 24. The other end of the primary Winding 23 is connected through the ignition switch 17 to the positive terminal of battery 10.

The charging circuit includes the secondary winding 25 of transformer 24 connected in series with a diode rectifier 26, a storage capacitor 27, and the primary winding 23 of an output transformer 30. This circuit charges the storage capacitor 27 each time the contacts 11 are closed. The discharge circuit includes storage capacitor 27, primary winding 28, and a gaseous discharge device 31 which is controlled to pass current by a tiring electrode coupled through a capacitor 32 and a resistor 33 to the secondary winding 34 of tiring transformer 22. The output circuit includes a secondary winding 35 on output transformer 30, a distributor 36, and a plurality of spark Vplugs 37. The distributor 36 includes the usual stator electrodes plus a rotatable arm 3S controlled to revolve by shaft 13 which also turns cam 12.

The operation of this device is as follows:

When the ignition switch 17 is opened no current can iiow through the system. When the switch 17 is closed, and the contacts 11 are open (just prior to closing) there is no battery current through either of windings 15 or 1S because the base of transistor 2d is biased to cut-off and no current can flow through its emittercollector circuit.

When the breaker points 11 close, a small current 40 (FIG. 2B) flows from the battery 10 through winding 15 and resistor 14 (assuming switch 45 open). This current is so small it produces no operating results except to create a magnetic iux in the core of transformer 16.

When the points 11 are next opened, the magnetic flux in the core of transformer 16 collapses Iand a voltage pulse -is generated in winding 13, biasing the transistor 20 for conductance for a short time and passing acurrent pulse 41 (FIG. 2B) to the base which permits a large current to tiow in the emitter-collector circuit through windings 21 and 23 and the battery. This current creates a magnetic iiux in the core of transformer 24. This current pulse 42 applies a positive potential to the tiring electrode of thyratron 31 causing it t'o conduct and discharge storage capacitor 27 through the thyratron and primary winding 23. This discharge Vpulse produces a lsharp output pulse 43 which is applied through the distributor '36 to one of the spark plugs. Y

When the base current pulse is reduced to zero, the ux in the core of transformer 24 collapses and a high voltage charging pulse is generated in winding 25 which charges storage capacitor 27 through diode 26. This charging pulse is generated some time after the ring of the thyratron and the gas in the thyratron has time to deionize.

lt should be noted that other voltages are generated during the operating cycle but they contribute nothing to the generation of the output pulse. At the start of pulse 41 a voltage is generated in winding 25 but this pulse applies a negative potential to the diode anode 26 and no conduction results. Also, at the end of pulse 41, a pulse is generated in secondary winding 34, but this tends to apply a negative potential to the ring electrode of the thyratron 31 which causes no result. The diode rectifier 44 bypasses a large percentage of this negative pulse and reduces its effect on the other circuits.

A starting circuit may be added to the device for compensating Vtor low battery voltage when the engine is cold or for any other reason. This circuit includes the auxiliary switch 45 which is closed only when the starter switch d6 is closed. The start circuit also includes a second primary winding 47on the core of transformer 16. FIGS. 3 yand 4 show the physical relationship of this winding toY the first primary winding 15. Vhen switch 45 is closed, the currents through windings 15 and 47 both generate magnetic Aflux lines in the central part of the core which are aiding and a strong pulse is pro.

duced in winding 18 when kthese currents are broken even if the battery voltage is only half its rated value. As soon as the starter switch 46 is opened, auxiliary switch 45 is opened and the operation continues as described above. The core shapes shown in FIGS. 3 and 4 are two possible arrangements which provide eicient operation when either one or both of the primary windings are connected.

The circuit shown in FIG. 5 includes an alternative arrangement of transformer connections for tiring the thyratron. The same charging transformer 24 is used except that the secondary winding 34 is coupled to the ring electrode through another transformer 50. With this connection, a diode 51 may be connected -in series with winding-34 and during the generation of the charging pulse which charges capacitor 27, no current ows to primary winding 52. There is no pulse current which drives the ring electrode of thyratron 31 negative to cause ionizing which might fire the thyratron off time. When the points open and pulse 41 is generated, the iiring electrode is made positive in the usual manner and the tube conducts.

' From the above description it is obvious that a novel control circuit for ignition systems has been developed which conserves battery power, limits contact breaker current, and provides a high voltage pulse for the spark plugs which has a fast rise time and is more dependable than pulses provided by prior art systems.

The foregoing'disclosure yand drawings aremerely illustrative of the principles of this invention and are not to beinterpreted in a limiting sense. The only limitations are to be determined by theY scope of the appended claims.

I claim:

1. An ignition system for internal combustion engines, having a plurality of combustion chambers each including a piston comprising:l

(a) a source of direct current;

(h) a pair of contacts controlled to open and close in timed relation with the movement of the pistons in the combustion chambers;

(c) a control transformer having a primaryrwinding and a secondary winding on a ferromagnetic core;

(d) a first magnetic storage circuit for generating a magnetic ux in the core of the control transformer when the pair of contacts close; said iirst magnetic d storage circuit including in series connection, the source of direct current, the pair of contacts, and the primary winding of the control transformer;

(e) a transistor having a base, a collector, and an emitter, the base being connected to one terminal of the secondary winding of the control transformer, the emitter coupled to another terminal of the secondary winding, and its collector connected to the negative terminal of the source of direct current;

(f) a charging transformer including a primary Winding and a secondary winding on a ferromagnetic core;

(g) a second magnetic storage circuit for generating a magnetic iiux in the core of the charging transformer when the contacts open; said second magnetic storage circuit including the source of direct current, the primary winding of the charging transformer, the secondary winding of the control transformer, and the emitter-collector electrodes of the transistor;

(h) a storage capacitor for `storing an electrical charge;

(i) a distributor;

(j) a plurality of spark plugs;

(k) an output transformer having a primary Winding and a secondary winding, said secondary winding connected to the plurality of spark plugs through the distributor;

(l) a charging circuit for charging the storage capacitor when the current in the primary winding of the charging transformer is cut off; said charging circuit including in series connection, the secondary winding of the charging transformer, a rectifier diode, the storage capacitor, and the primary Winding of the output transformer;

(m) a gaseous discharge device for discharging the storage capacitor, said device including an anode, a cathode, and a ring electrode;

(n) a discharge circuit for discharging the storage capacitor when the contacts open, said discharge circuit including in series connection, the storage capacitor, the anode-cathode electrodes of the discharge device, land the primary winding of the output transformer;

(o) and coupling meansconnected between the control transformer and the tiring electrode of the discharge device for making the device conductive when the contact points open.

2. An ignition system as claimed in claim 1 including a starting switch and a starting motor and wherein a second primary winding is provided on the control transformer and is switched into the battery circuit in parallel with the first primary winding by a switch coupled to the starting switch in series with the starting motor.

3. An ignition system as claimed in claim 1 wherein a firing transformer is coupled between the circuit containing the primary winding of the charging transformer and the tiring electrode in said discharge device.

4. An ignition system as claimed in claim 3 wherein said firing transformer comprises the primary winding or" the charging transformer and a secondary winding on the same core, said secondary winding coupled to the ring electrode through another coupling transformer.

References Cited by the Examiner UNITED STATES PATENTS 2,980,822 4/61 Short 315-209 2,981,865 4/61 Fernbach 315-209 3,032,684 5/62 Kuykendall 315-209Y 3,032,685 5/62 Loomis 315-209 3,049,642 8/62 Quinn 315-209 DAVID J. GALVIN, Primary Examiner.

GEORGE N. WESTBY, Examiner. 

1. AN IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES, HAVING A PLURALITY OF COMBUSTION CHAMBERS EACH INCLUDING A PISTON COMPRISING: (A) A SOURCE OF DIRECT CURRENT; (B) A PAIR OF CONTACTS CONTROLLED TO OPEN AND CLOSE IN TIMED RELATION WITH THE MOVEMENT OF THE PISTONS IN THE COMBUSTION CHAMBERS; (C) A CONTROL TRANSFORMER HAVING A PRIMARY WINDING AND A SECONDARY WINDING ON A FERROMAGNETIC CORE; (D) A FIRST MAGNETIC STORAGE CIRCUIT FOR GENERATING A MAGNETIC FLUX IN THE CORE OF THE CONTROL TRANSFORMER WHEN THE PAIR OF CONTACTS CLOSE; SAID FIRST MAGNETIC STORAGE CIRCUIT INCLUDING IN SERIES CONNECTION, THE SOURCE OF DIRECT CURRENT, THE PAIR OF CONTACTS, AND THE PRIMARY WINDING OF THE CONTROL TRANSFORMER; (E) A TRANSISTOR HAVING A BASE, A COLLECTOR, AND AN EMITTER, THE BASE BEING CONNECTED TO ONE TERMINAL OF THE SECONDARY WINDING OF THE CONTROL TRANSFORMER, THE EMITTER COUPLED TO ANOTHER TERMINAL OF THE SECONDARY WINDING, AND ITS COLLECTOR CONNECTED TO THE NEGATIVE TERMINAL OF THE SOURCE OF DIRECT CURRENT; (F) A CHARGING TRANSFORMER INCLUDING A PRIMARY WINDING AND A SECONDARY WINDING ON A FERROMAGNETIC CORE; (G) A SECOND MAGNETIC STORAGE CIRCUIT FOR GENERATING A MAGNETIC FLUX IN THE CORE OF THE CHARGING TRANSFORMER WHEN THE CONTACTS OPEN; SAID SECOND MAGNETIC STORAGE CIRCUIT INCLUDING THE SOURCE OF DIRECT CURRENT, THE PRIMARY WINDING OF THE CHARGING TRANSFORMER, THE SECONDARY WINDING OF THE CONTROL TRANSFORMER, AND THE EMITTER-COLLECTOR ELECTRODES OF THE TRANSISTOR; (H) A STORAGE CAPACITOR FOR STORING AN ELECTRICAL CHARGE; (I) A DISTRIBUTOR; (J) A PLURALITY OF SPARK PLUGS; (K) AN OUTPUT TRANSFORMER HAVING A PRIMARY WINDING AND A SECONDARY WINDING, SAID SECONDARY WINDING CONNECTED TO THE PLURALITY OF SPARK PLUGS THROUGH THE DISTRIBUTOR; (1) A CHARGING CIRCUIT FOR CHARGING THE STORAGE CAPACITOR WHEN THE CURRENT IN THE PRIMARY WINDING OF THE CHARGING TRANSFORMER IS CUT OFF; SAID CHARGING CIRCUIT INCLUDING IN SERIES CONNECTION, THE SECONDARY WINDING OF THE CHARGING TRANSFORMER, A RECTIFIER DIODE, THE STORAGE CAPACITOR, AND THE PRIMARY WINDING OF THE OUTPUT TRANSFORMER; (M) A GASEOUS DISCHARGE DEVICE FOR DISCHARGING THE STORAGE CAPACITOR, SAID DEVICE INCLUDING AN ANODE, A CATHODE, AND A FIRING ELECTRODE; (N) A DISCHARGE CIRCUIT FOR DISCHARGING THE STORAGE CAPACITOR WHEN THE CONTACTS OPEN, SAID DISCHARGE CIRCUIT INCLUDING IN SERIES CONNECTION, THE STORAGE CAPACITOR, THE ANODE-CATHODE ELECTRODES OF THE DISCHARGE DEVICE, AND THE PRIMARY WINDING OF THE OUTPUT TRANSFORMER; (O) AND COUPLING MEANS CONNECTED BETWEEN THE CONTROL TRANSFORMER AND THE FIRING ELECTRODE OF THE DISCHARGE DEVICE FOR MAKING THE DEVICE CONDUCTIVE WHEN THE CONTACT POINTS OPEN. 